Specific Imaging Findings

Sturge–Weber syndrome (SWS) shows a spectrum of findings related to leptomeningeal angiomatous changes, which consequently affect the brain parenchyma. There is atrophy of the affected brain, seen as widening of the cortical sulci and enlargement of the ventricles. Cortical gyriform calcifications are hyperdense on CT and hypointense on all MR sequences. There is an avid leptomeningeal contrast enhancement in the affected area, prominent medullary veins and enlargement of the ipsilateral choroid plexus, which can be seen on postcontrast CT or MRI. T2*-weighted MR sequences readily show calcifications, and susceptibility-weighted images (SWI) can show prominent medullary veins and sometimes the angiomatous changes without contrast administration. Intracranial SWS findings are usually unilateral, with a subtle predilection for the posterior portions of the brain, but may affect the whole cerebral hemisphere. However, SWS can also be bilateral or focal/isolated to one or a few lobes. Hypertrophy of the skull and paranasal sinuses (Dyke–Davidoff–Masson syndrome), and globe enlargement with abnormal enhancement, may also be present. Infratentorial pial angiomas are common but usually very subtle.

Pertinent Clinical Information

Patients with SWS generally develop normally until the onset of seizures, which over time become progressively refractory to medication. The overwhelming majority have a port-wine stain, usually along the V1 segment of the trigeminal nerve distribution, ipsilateral to the intracranial angiomatous changes. However, cases of SWS without port-wine stain have been described. Most patients are mentally retarded and 30% have hemiparesis. The ocular manifestations include choroidal and scleral or episcleral telangiectasia with glaucoma and enlarged globe. Progression in neurologic deficits occurs in some patients, but this is quite variable. Mild cases with subtle imaging findings that are discovered later in childhood and with minimal symptoms have also been described.